System and method for proxying data access commands in a clustered storage system

• US 7,340,639 B1
• Filed: 03/26/2004
• Issued: 03/04/2008
• Est. Priority Date: 01/08/2004
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Lee, Herman, Rajan, Vijayan
• Primary Examiner(s): PEIKARI, BEHZAD
• Application Number:
  US10/811,095
• Time in Patent Office: 1,439 Days
• Field of Search: None
• US Class Current: 714/6.31
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A system and method proxies data access commands across a cluster interconnect between storage appliances in a cluster. Each storage appliance activates two ports for data access, a local port for data access requests directed to clients of the storage appliance and a proxy port for data access requests directed to the partner storage appliance. Clients utilizing multi-pathing software may send data access requests to either the local port of the storage appliance or the proxy port of the storage appliance. The system and method improve high availability especially during a loss of connectivity due to non-storage appliance hardware failure.

Claims

1. A method for proxying data access commands from a first storage system to a second storage system in a storage system cluster, comprising:

in response to a failure in communication between a client and the second storage system, receiving, at a proxy port on the first storage system, a data access command at the first storage system that is directed to the second storage system;

forwarding the received data access command to the second storage system via a cluster interconnect;

processing the data access command at the second storage system;

returning a response from the second storage system to the first storage system via the cluster interconnect; and

sending a response to the data access command to the client from the first storage system.

2. The method of claim 1 wherein the storage systems are storage appliances.

3. The method of claim 1 wherein the proxy port comprises a physical port.

4. The method of claim 1 wherein the proxy port comprises a virtual port associated with a physical port.

5. The method of claim 1 wherein the response comprises requested read data.

6. The method of claim 1 wherein the response comprises an acknowledgement of a write operation.

7. The method of claim 1 wherein the response comprises a predetermined set of read data.

8. The method of claim 1 wherein the cluster interconnect comprises a direct link between the first storage system and the second storage system.

9. A method for proxying data access commands in a first storage system to a second system in a storage system cluster, comprising the:

in response to a failure in communication between a client and the second storage system, receiving, at a proxy port on the first storage system, a data access command at the first storage system that is directed to the second storage system;

analyzing a received data access command at the first storage system;

forwarding the received data access command to the second storage system; and

processing the received data access command at the second storage system.

10. The method of claim 9 further comprising;

returning a response from the second storage system to the first storage system; and

sending a response to the data access command to the client from the first storage system.

11. The method of claim 10 wherein the response comprises requested read data.

12. The method of claim 10 wherein the response comprises an acknowledgement of the write operation.

13. The method of claim 9 wherein the step of forwarding further comprises forwarding the data access command to the second storage system via a cluster interconnect.

14. The method of claim 13 wherein the cluster interconnect comprises a fibre channel link.

15. The method of claim 13 wherein the cluster interconnect comprises a direct link between the first storage system and the second storage system.

16. The method of claim 9 wherein the proxy port comprises a physical port.

17. The method of claim 9 wherein the proxy port comprises a virtual port associated with the physical port.

18. A computer readable storage device having stored thereon program instructions for executing on a computer, for proxying data access commands from a first storage system to a second storage system in a storage system cluster, wherein the program instructions when executed by the computer perform the steps of:

in response to a failure in communication between a client and the second storage system, receiving, at a proxy port on the first storage system, a data access command at the first storage system that is directed to the second storage system;

forwarding the received data access command to the second storage system via a cluster interconnect;

processing the data access command at the second storage system;

returning a response from the second storage system to the first storage system via the cluster interconnect; and

sending a response to the data access command to the client from the first storage system.

19. A system for proxying data access commands from a first storage system to a second storage system connected via a cluster interconnect, the system comprising:

in response to a failure in communication between a client and the second storage system, a proxy port configured to receive a data access command at the first storage system that is directed to the second storage system;

means for forwarding the received data access command to the second storage system via a cluster interconnect;

means for processing the data access command at the second storage system;

means for returning a response from the second storage system to the first storage system via the cluster interconnect; and

means for sending a response to the data access command to the client from the first storage system.

20. The system of claim 19 wherein storage systems are storage appliances.

21. The system of claim 19 wherein the proxy port comprises a physical port.

22. The system of claim 19 wherein the proxy port comprises a virtual port associated with a physical port.

23. The system of claim 19 wherein the response comprises requested read data.

24. The system of claim 19 wherein the response comprises an acknowledgement of a write operation.

25. The system of claim 19 wherein the response comprises a predetermined set of read data.

26. A method for proxying data access commands from a first storage system to a second storage system in a storage system cluster, the method comprising:

in response to a failure in communication between a client and the second storage system, receiving, at a proxy port on the first storage system, a data access command at the first storage system that is directed to the second storage system;

forwarding a data access command from the first storage system to the second storage system;

processing the data access command at the second storage system; and

returning a response from the second storage system to the first storage system.

27. The method of claim 26 further comprises sending a response to the data access command from the first storage system.

28. The method of claim 26 wherein the data access command is forwarded via a cluster interconnect.

29. The method of claim 26 further comprises returning the response from the first storage system to the client.

30. The method of claim 29 wherein the response is returned via the cluster interconnect.

31. A method for proxying data access commands from a first storage system to a second storage system in a storage system cluster, comprising:

receiving a data access command at the first storage system;

determining the data access command was received at a proxy port on the first storage system;

passing the data access command to a local virtual adapter;

forwarding the received data access command to the second storage system via a cluster interconnect;

processing the data access command at the second storage system;

returning a response from the second storage system to the first storage system via the cluster interconnect; and

sending a response to the data access command to a client from the first storage system.

32. The method of claim 31, wherein the data access command is directed to the second storage system.

33. The method of claim 31, wherein the proxy port comprises a physical port.

34. The method of claim 31, wherein the proxy port comprises a virtual port.

35. The method of claim 31, wherein the first storage system receives the data access command in response to a communication failure between the client and the second storage system.

36. A system for proxying data access commands from a first storage system to a second storage system in a storage system cluster, comprising:

a proxy port on the first storage system, the proxy port to receive a data access command that is directed to the second storage system in response to a failure in communication between a client and the second storage system;

a local virtual adapter on the first storage system, the local virtual adapter to forward the received data access command to the second storage system via a cluster interconnect;

a processor on the second storage system, the processor configured to process the data access command at the second storage system;

a partner virtual adapter on the second storage system, the partner virtual adapter to return a response from the second storage system to the first storage system via the cluster interconnect; and

a network adapter to send a response to the data access command to a client from the first storage system.

37. The system of claim 36, wherein the first storage system further comprises a local virtual target module to determine the data access command was received at a proxy port on the first storage system, and the local virtual target module to pass the data access command to the local virtual adapter.

38. The system of claim 36, wherein the proxy port comprises a physical port.

39. The system of claim 36, wherein the proxy port comprises a virtual port.